Dynamic chirality of (E)-5-cyclononen-1-one and its enolate
Katsuhiko Tomooka1, Takayuki Ezawa, Hiroko Inoue
1Institute for Materials Chemistry and Engineering, Kyushu University, Kasuga, Fukuoka 816-8580, Japan. ktomooka@cm.kyushu-u.ac.jp
Journal of the American Chemical Society
|January 27, 2011
Summary
The study found that while (E)-5-cyclononen-1-one has weak planar chirality, its derived enolates exhibit strong planar chirality. These enolates can be prepared using enzymatic hydrolysis and act as chiral nucleophiles.
Area of Science:
- Organic Chemistry
- Stereochemistry
- Enzymatic Catalysis
Background:
- Planar chirality is a type of chirality where a molecule is chiral due to a planar arrangement of atoms.
- Topological constraints are crucial for maintaining robust chirality in organic molecules.
- Enolates are versatile intermediates in organic synthesis, often used as nucleophiles.
Purpose of the Study:
- To investigate the planar chirality of (E)-5-cyclononen-1-one and its derived enolates.
- To explore the preparation of enantioenriched enolates using enzymatic methods.
- To assess the utility of these enolates as chiral nucleophiles in synthesis.
Main Methods:
- Synthesis of (E)-5-cyclononen-1-one.
- Generation of enolates from (E)-5-cyclononen-1-one.
- Enzymatic hydrolysis for enantioselective preparation of enolates.
- Evaluation of enolate nucleophilicity and stereochemical outcomes.
Main Results:
- (E)-5-cyclononen-1-one exhibits limited planar chirality due to insufficient topological constraint.
- Enolates derived from (E)-5-cyclononen-1-one demonstrate robust planar chirality.
- Enantioenriched enolates were successfully prepared via enzymatic hydrolysis.
- The enantioenriched enolates function effectively as chiral nucleophiles.
Conclusions:
- The enolates of (E)-5-cyclononen-1-one are valuable chiral building blocks.
- Enzymatic hydrolysis provides an efficient route to enantioenriched planar chiral enolates.
- These findings open new avenues for asymmetric synthesis using planar chiral nucleophiles.
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